This invention relates to mechanical power transmission systems and particularly drive systems on agricultural harvesting machines in which a capability for varying speed and for occasional direction reversal are advantageous, such as in the drive for a header comprising gathering and feeding units.
It is known to mount variable speed V-belt drives on the feeding unit of a header for driving both its gathering and feeding units. A drive of this general type is shown in U.S. Pat. No. 3,759,021 issued to Schreiner et al. and sharing a common assignee with the present application. However, because of demands for higher performance and higher capacity harvesting machines, individual drives are being required to transmit ever higher horsepowers. Considerations of efficiency and the need to limit overall machine size make it desirable to minimize the overall dimensions of such drives and their components.
At the same time, operators and owners of harvesting machines are requiring designs giving more attention to safety and convenience in operation. In difficult crop conditions it is possible to plug even the best of machines but the increasing size and capacity of modern machines are making it less practicable to clear blockages by hand unassisted by any power means. The need for some means of powered reversal of gathering and feeding units has long been known and a few reversing systems have been offered. These have tended to be bulky and relatively expensive single purpose units superimposed on existing drive systems rather than integrated into them. Typically the drive reversing systems offered have been applied only to parts of the feeding or gathering units, rather than to the complete gathering and feeding system and have enjoyed only limited commercial success. To be successful, reversers must be reliable, simple, low cost, compact, convenient to operate and not interfere with or detract from normal operation of the machine.